A1C of 5% is an average glucose of 97 mg/dL

Estimated average glucose at A1C 5%

97 mg/dL

In mmol/L: 5.4 mmol/L
A1C entered: 5.0%
ADA range: below the range the ADA defines as prediabetes

5.0% translates to an average glucose of about 97 mg/dL, which is 5.4 mmol/L in the units used across the UK, Australia and Canada. The IFCC equivalent of the A1C itself is close to 31 mmol/mol.

This sits under the ADA prediabetes threshold. A single value summarises roughly the last three months of glucose exposure; what a clinician actually reads is the trend across several tests, which one result cannot show.

To put the scale in context: 5.1% estimates out at around 100 mg/dL, some 3 mg/dL above this figure. Because assay tolerance spans roughly 0.5 percentage points, a shift of one tenth tells you very little on its own.

Before reading much into this exact figure, note that NGSP certification allows a certified assay to differ from the reference method by about 0.5 percentage points. Two draws from the same person in the same week can land either side of a boundary without anything having changed.

If you are going to take one thing from this page, take the comparison rather than the reading: a number in isolation is trivia, and the same number tracked over time is information.

Which glucose unit you see is a matter of geography: the United States and India generally report mg/dL, while the UK, Australia and Canada generally report mmol/L.

Anything that alters red blood cell turnover — anaemia, recent blood loss, a transfusion, pregnancy, chronic kidney disease, some haemoglobin variants — moves A1C independently of glucose, in either direction.

Convert a different A1C value

A1C to estimated average glucose, 4.5% to 5.5%
A1C	eAG (mg/dL)	eAG (mmol/L)
4.5%	82 mg/dL	4.6 mmol/L
4.6%	85 mg/dL	4.7 mmol/L
4.7%	88 mg/dL	4.9 mmol/L
4.8%	91 mg/dL	5.1 mmol/L
4.9%	94 mg/dL	5.2 mmol/L
5.0%	97 mg/dL	5.4 mmol/L
5.1%	100 mg/dL	5.5 mmol/L
5.2%	103 mg/dL	5.7 mmol/L
5.3%	105 mg/dL	5.8 mmol/L
5.4%	108 mg/dL	6 mmol/L
5.5%	111 mg/dL	6.2 mmol/L

Computed with eAG (mg/dL) = 28.7 x A1C - 46.7 (Nathan 2008). mmol/L is derived from mg/dL using the glucose factor 18.0182.

Estimated average glucose (ADAG / Nathan) — eAG (mg/dL) = 28.7 x A1C - 46.7. Verified 2026-07-30 against Nathan et al., Diabetes Care 2008 (ADAG study) (A population regression: in the ADAG study, individuals at the same A1C had meaningfully different mean glucose. The A1C assay itself carries about +/- 0.5 percentage points under NGSP certification.)

Official sources

Nathan DM et al., Translating the A1C Assay Into Estimated Average Glucose Values, Diabetes Care 2008 — The ADAG study that produced the eAG equation used on this page.
American Diabetes Association — Standards of Care in Diabetes — Where the A1C ranges quoted here are defined.
NGSP — A1C assay standardisation and certification criteria — Why two lab results half a point apart can mean nothing changed.

Frequently asked questions

How much average glucose is an A1C of 5.0%?

An estimated average glucose near 97 mg/dL, or 5.4 mmol/L. This applies the ADA-published conversion to an A1C of 5.0%, and describes roughly the last three months.

Does 5.0% count as prediabetes or diabetes?

The ADA describes 5.0% as below the range the ADA defines as prediabetes. That is a definition of a numeric range rather than a diagnosis: the ADA asks clinicians to confirm results with a repeat test and to read them alongside your history.

Is 5.0% a target?

This page converts a number rather than recommending one. Glycemic targets are individualised by a clinician according to your diagnosis, your other results and your risk of hypoglycaemia.

Would a different lab report the same 5.0%?

Not necessarily. Analytical methods vary between laboratories, and a point-of-care fingerstick can read differently from a venous draw, so comparisons are cleanest within one lab.

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